An IterableInterval is not guaranteed to iterate over all
coordinates of its containing Interval. In the typical case of a
hyperrectangular image, it will do so; however, there are some
IterableIntervals which visit only a subset of the Interval
coordinates. For example, the imglib2-roi library provides means to
model regions of interest (ROIs), along with the ability to iterate over
coordinates within a particular ROI; see e.g.
net.imglib2.roi.labeling.LabelRegion.